1. Field of the Invention
The present invention relates to a digital audio synchronous player which digitally records and/or plays back audio signals and particularly relates to a digital audio synchronous player which generates a synchronizing signal and conducts synchronous playback based on this synchronizing signal.
2. Prior Art
Conventional digital audio recorders/players respectively have their own master clocks, each of which generates a clock (a clock signal) corresponding to fixed sampling frequency Fs (for example, 48 kHz, 44.1 kHz, 32 kHz, and the like), and conduct recording and playback of musical tones (audio signals) and the like based on the generation periods of these clocks.
However, there are slight deviations among the clock-generation-timings of the master clocks. These deviations are produced by external causes such as temperature variations, not only among different-type players, but also among the same-type players.
When a plurality of conventional digital audio synchronous players using such master clocks simultaneously play back musical tones, because of deviations among their playback speeds, it is difficult to accurately conduct simultaneous playback among the plurality of conventional digital audio synchronous players.
Technology was conventionally known in which time codes were stored with audio data, and synchronous playback was conducted based on these time codes. This technology will be explained, for example, using a case in which the synchronous play of two players is conducted.
First, as shown in FIG. 3, two digital audio players are connected to a synchronizer, and during playback, time codes are read out with the audio data in each player. The synchronizer uses the time code read out from one player as a standard, and governs the reading speed of the other player so that the time code of the other player is in agreement. By means of this, synchronization can be conducted so that the playback speeds of the two players are in agreement. That is to say, one player is used as a master, while the other player is used as a slave.
Furthermore, the synchronous playback among the digital audio players and MIDI sequencers (instruments having the MIDI) is fundamentally identical to that given above. However, the synchronous playback of the MIDI sequencers has been considered only between the MIDI sequencers themselves, it is necessary to provide, as shown in FIG. 4, in place of the synchronizer described above, an interface which reads the master time code and converts this time code to a MIDI clock. The "MIDI" means "Musical Instrument Digital Interface".
In the two methods described above, it is necessary to provide a special track for the storing of time codes which is separate from the track which stores audio data. However, when this is intended as a storage medium, the special track for the time code is a completely wasted region, so that there was a problem in that, with respect to digital audio recorders/players, the number of tracks capable of recording was reduced by the number of special tracks for the time codes.